Plasma display panels (PDPs) are one of the leading candidates in the competition for large-size, high-brightness, high-contrast-ratio flat panel displays, suitable for high definition television (HDTV) wall-mounted monitors. Their advantages are high resolution, wide viewing angle, low weight, and simple manufacturing process for fabrication.
Recent progress of PDP technology development and manufacturing has been remarkable. However, there are still problems that need to be resolved to popularize the PDP as a home commodity. One of the most critical issues in ongoing PDP research is the improvement of the luminous efficiency, which is still low compared to conventional cathode ray tube displays. Another important problem is the relatively high operating voltages.
PDP cells are small (cell height is ˜150 μm) and provide limited access for diagnostic measurements. As a result, experimental studies of the transient plasma discharges in PDPs are extremely difficult, and computer-based modeling is currently essential for understanding PDP physics and optimizing its operation. Computer simulations are effective in identifying the basic properties of the discharge dynamics and the dominant mechanisms of light emission. In addition, simulation models are usually successful in predicting the effects on the performance of the device of variations in design parameters, such as cell geometry, applied voltage waveforms, and gas mixture. Although simulation results are usually in qualitative rather than quantitative agreement with experimental display measurements, they are used for PDP design.
Typical color plasma displays consist of two glass plates, each with parallel electrodes deposited on their surfaces. The electrodes are covered with a dielectric film. The plates are sealed together with their electrodes at right angles, and the gap between the plates is first evacuated and then filled with an inert gas mixture. A protective MgO layer is deposited above the dielectric film. The primary role of this layer is to decrease the breakdown voltage due to the high secondary-electron emission coefficient of MgO. The UV photons emitted by the discharge hit the phosphors deposited on the walls of the PDP cell and are converted into visible photons. Each cell contains a specific type of phosphor that emits one primary color, red, green or blue.
The most common type of color plasma display is the coplanar-electrode PDP. Referring to FIG. 1 a prior art coplanar display is shown. In this PDP type each cell is formed by the intersection of a pair of transparent sustain electrodes 12, 13 on the front plate 14, and an address electrode 16 on the back plate 17. Dielectric layers 18 and 19 cover the electrodes. The dielectric film 18 is protected by MgO layer 21. A phosphor layer 22 is deposited above the dielectric film 19. Walls 23 define its various cells.
During operation, a periodic voltage with a frequency of 50-350 kHz is continuously applied between each pair of sustain electrodes. The amplitude of the sustain voltage is below the breakdown voltage. A cell is turned ON by applying a write voltage pulse between the address electrode and one of the sustain electrodes. The discharge which is initiated results in the deposition of surface charge on the dielectric layers covering these two electrodes. The superposition of the electric field induced by the deposited surface charge and of the electric field of the sustaining voltage results in the ignition of sustain discharges between the pair of sustain electrodes. The UV photons emitted by the discharge strike the phosphor layer and are converted into visible photons.